Fix install target and versioning

internal/version.go

@@ -2,17 +2,49 @@ package internal
 
 import (
 	"fmt"
+	"runtime/debug"
+	"strings"
+)
+
+const (
+	defaultVersion = "0.0.0"
+	defaultCommit  = "HEAD"
+	defaultBuild   = "0000-01-01:00:00+00:00"
 )
 
 var (
-	// Version release version
-	Version = "0.0.1"
+	// Version is the tagged release version in the form <major>.<minor>.<patch>
+	// following semantic versioning and is overwritten by the build system.
+	Version = defaultVersion
 
-	// Commit will be overwritten automatically by the build system
-	Commit = "HEAD"
+	// Commit is the commit sha of the build (normally from Git) and is overwritten
+	// by the build system.
+	Commit = defaultCommit
+
+	// Build is the date and time of the build as an RFC3339 formatted string
+	// and is overwritten by the build system.
+	Build = defaultBuild
 )
 
-// FullVersion returns the full version and commit hash
+// FullVersion display the full version and build
 func FullVersion() string {
-	return fmt.Sprintf("%s@%s", Version, Commit)
+	var sb strings.Builder
+
+	isDefault := Version == defaultVersion && Commit == defaultCommit && Build == defaultBuild
+
+	if !isDefault {
+		sb.WriteString(fmt.Sprintf("%s@%s %s", Version, Commit, Build))
+	}
+
+	if info, ok := debug.ReadBuildInfo(); ok {
+		if isDefault {
+			sb.WriteString(fmt.Sprintf(" %s", info.Main.Version))
+		}
+		sb.WriteString(fmt.Sprintf(" %s", info.GoVersion))
+		if info.Main.Sum != "" {
+			sb.WriteString(fmt.Sprintf(" %s", info.Main.Sum))
+		}
+	}
+
+	return sb.String()
 }